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61.
We employed the ArcGIS plug-in package PRO-GRADE (Lin et al. 2009), developed for zonation of recharge/discharge (R/D) for modeling two-dimensional aquifer systems, to develop alternative R/D zonations for an existing three-dimensional groundwater flow model of a complex hydrogeologic setting. Our process began by intersecting PRO-GRADE output with the existing model's 4-zone R/D representation to develop a model having 12 R/D zones (R12) and then calibrating the resulting model using PEST. We then revised the R12 zonation using supplementary GIS data to develop a 51-zone R/D zonation (R51). From R51, we developed a series of daughter models having 40, 30, 28, and 18 R/D zones by removing zones from R51 if calibration resulted in little change in the zone's starting R/D rate and/or if the model was insensitive to the zone's R/D rate. For these models (R40N, R30N, R28N, and R18N), we used the ArcGIS Nibble tool to rapidly and consistently reassign model cells within eliminated zones of R51 to the zone of the nearest model cell in a retained zone having the same starting value. R12, R51, R40N, R30N, R28N, and R18N are all more accurate than the original model (R4), although improvements relative to stream discharge targets exceeded improvements relative to head targets. The models also executed with better numerical stability and less mass balance discrepancy than R4. These improvements demonstrate that R/D estimation in a complex shallow three-dimensional steady-state model can be improved with PRO-GRADE estimates of R/D when guided by calibration statistics and supplemental geographic data. 相似文献
62.
Carl Schmitt’s work on the political is extensively used as an intellectual point of departure in contemporary academic debates about political contestation. More precisely, Carl Schmitt’s friend versus enemy-distinction is invoked as an essential figuration of political contestation. At the same time, the past few years have seen the attention paid to the spatial thought of Carl Schmitt increase. However, references to the work of Carl Schmitt fail to take the embeddedness of his theories in a complex theological–political–spatial triangle into account. This article aims at joining these readings of Schmitt with regard to the current debate about contestation and space by analyzing the idiosyncratic connection between Carl Schmitt’s Catholic faith, especially in the figure of the katechon, his theory of the political and his conceptualization(s) of space. The underlying logic of his worldview becomes explicit by reviewing his concepts of (a) the nomos, (b) land and sea, (c) the Großraumordnung, as well as (d) the Partisan, which form the benchmarks of his work between the 1930s and the 1960s. Against this background we analyze the value of Schmitt’s work for the ongoing debate about contestation and space. Our core argument is that his understanding of the spatial–political nexus and his metaphysical worldview stand in contrast to contemporary conceptualizations of spatial–political relationships. 相似文献
63.
Michael Kühn Maja Tesmer Peter Pilz Robert Meyer Kurt Reinicke Andrea F?rster Olaf Kolditz Dirk Sch?fer 《Environmental Earth Sciences》2012,67(2):311-321
The joint research project CLEAN was conducted in the years 2008?C2011 by a German research and development (R&D) alliance of 16 partners from science and industry. The project was set-up as pilot project to investigate the processes relevant to enhanced gas recovery (EGR) by the injection of CO2 into a subfield of the almost depleted Altmark natural gas field. Despite the setback that permission for active injection was not issued by the mining authority during the period of the project, important results fostering the understanding of processes linked with EGR were achieved. Work carried out led to a comprehensive evaluation of the EGR potential of the Altmark field and the Altensalzwedel subfield in particular. The calculated safety margins emphasize that technical well integrity of the 12 examined boreholes is given for EGR without a need for any further intervention. The laboratory and field tests confirm that the Altensalzwedel subfield is suitable for the injection of 100,000?t of CO2. Numerical simulations provide sound predictions for the efficiency and safety of the EGR technology based on the CO2 injection. The development and testing of different monitoring techniques facilitate an improved surveying of CO2 storage sites in general. The CLEAN results provide the technological, logistic and conceptual prerequisites for implementing a CO2-based EGR project in the Altmark and provide a benchmark for similar projects in the world. 相似文献
64.
65.
Preface: Proceedings of the 5th International Symposium on Lithographic Limestone and Plattenkalk 总被引:1,自引:0,他引:1
Daniel Marty Jean-Paul Billon-Bruyat Christian A. Meyer Loïc Costeur Basil Thüring 《Swiss Journal of Geoscience》2011,104(1):1-29
Magmatic rocks from the pre-Mesozoic basements of the Sambuco and Maggia nappes have been dated by U–Pb zircon ages with the LA-ICPMS technique. Several magmatic events have been identified in the Sambuco nappe. The mafic banded calc-alkaline suite of Scheggia is dated at 540 Ma, an age comparable to that of mafic rocks in the Austroalpine Silvretta nappe. The Sasso Nero peraluminous augengneiss has an age of 480–470 Ma, like many other “older orthogneisses” in Alpine basement units. It hosts a large proportion of inherited zircons, which were dated around 630 Ma, a Panafrican age indicating the Gondwanan affiliation of the Sambuco basement. The calc-alkaline Matorello pluton yielded ages around 300 Ma, similar to numerous Late Carboniferous intrusions in other basement units of the Lower Penninic (Monte Leone, Antigorio, Verampio) and Helvetic domains (Gotthard and other External Crystalline Massifs). Associated lamprophyric dykes are slightly younger (300–290 Ma), like similar dykes sampled in gneiss blocks included in the sedimentary cover of the underlying Antigorio nappe (290–285 Ma). The Cocco granodiorite and Rüscada leucogranite, both intruding the basement of the neighbouring Maggia nappe, yielded ages of ca. 300–310 Ma, identical within errors to the age of the Matorello pluton. They are significantly older than former age determinations. This age coincidence, coupled with remarkable petrologic similarities between the Cocco and Matorello granodiorites, strongly suggests paleogeographic proximity of the Sambuco and Maggia nappes in Late Carboniferous times. In recent publications these two nappes have been interpreted as belonging to distinct Mesozoic paleogeographic domains: “European” for Sambuco and “Briançonnais” for Maggia, separated by the “Valais” oceanic basin. In this case, the similarity of the Matorello and Cocco intrusions would demonstrate the absence of any significant transcurrent movement between these two continental domains. Alternatively, according to a more traditional view, Sambuco and Maggia might belong to a single large Alpine tectonic unit. 相似文献
66.
Evaluation of the environmental impacts of extreme floods in the Evros River basin using Contingent Valuation Method 总被引:2,自引:1,他引:1
India is among the top ten countries with the highest percentage of landslide fatalities for the past few years. Intense rainfall during the 2009 monsoon in the hilly district of Nilgiris, in the state of Tamilnadu in India, triggered landslides at more than 300 locations which affected road and rail traffic, destroyed buildings, caused the death of more than 40 people and left hundreds homeless. In this paper, three case histories from Nilgiris district are investigated: the slope failure of a railway track at Aravankadu, failure of retaining walls supporting buildings at Coonoor, failure of the slope and retaining wall along national highway (NH67) at Chinnabikatty. Laboratory investigations are carried out on soil samples collected at these sites. Soils at all the three locations have high fine content and low values of coefficient of permeability. Finite element analyses of all the three case histories were carried out using PLAXIS2D software in order to understand the failure mechanism and contributing factors. Slope stability analysis using strength reduction technique is carried out for the slope at Aravankadu to determine the critical slip surface and factor of safety. Results reveal that the increase in pore pressures led to a reduction in shear strength of the soil and consequently resulted in progressive failure of slope at Aravankadu site. Displacement analysis is carried out for Coonoor and Chinnabikatty sites. The results show that combined effect of surcharge load of building and high pore pressure led to intense shearing behind the retaining walls at Coonoor site. Results indicate occurrence of large displacements along the face and at toe of the slope at Chinnabikatty site. 相似文献
67.
68.
Geothermometric constraints on auriferous shear zones of the Renco mine in the Northern Marginal Zone of the late-Archaean,
granulite-facies Limpopo Belt in southern Zimbabwe indicate that deformation and associated mineralization occurred at temperatures
of at least 600 °C up to more likely 700 °C. Mid- to upper-amphibolite facies conditions during mineralization correspond
to the regional-scale retrogression of granulite facies wall rocks during the late-Archaean thrusting of high-grade metamorphic
rocks of the Northern Marginal Zone onto low- to medium-grade granite-greenstone terrains of the Zimbabwe craton. Mineral
assemblages indicate that the ore fluid was moderately oxidized with log fO2 values between 10−17 and 10−18 bars with high H2S activities of 0.25–0.75. Elements enriched in the shear zones include Au, S, Fe, Cu, Mo, Bi, Te, Ni, Co, and H2O, Au and Cu being the most enriched. Geochemically, Au correlates with Cu but not with S, which, together with the fact that
gold is only rarely intergrown or in direct contact with sulfides, possibly indicates a transport of gold as a chloride complex.
The siting of gold along fractures or within implosion breccias suggests that gold was precipitated due to fluid immiscibility
induced by catastrophic fluid pressure drops during seismic slip events. Fluid inclusions are predominantly CO2 (±CH4 ± N2)-rich, but petrographic work indicates that fluid inclusions have undergone extensive post-entrapment modifications due to
the pervasive recrystallization of mineral textures in the high-temperature shear zones. The mineralized shear zones are enriched
in 18O compared to wall-rock enderbites, which is interpreted to represent an influx of externally derived fluids of probably metamorphic
origin. Based on temporal and spatial relationships between mineralization, late-Archaean overthrusting of the Northern Marginal
Zone onto the Zimbabwe craton, and coeval amphibolite-facies hydration of granulites, we suggest that the Renco mineralization
formed in a mid-crustal environment from metamorphic fluids that were generated from dehydration of subcreted greenstone terrains
of the Zimbabwe craton.
Received: 27 October 1998 / Accepted: 13 August 1999 相似文献
69.
Structural controls of lode-gold mineralization by mafic dykes in late-Paleozoic granitoids of the Kochkar district, southern Urals, Russia 总被引:2,自引:0,他引:2
A. F. M. Kisters F. M. Meyer S. E. Znamensky I. B. Seravkin R. G. W. Ertl A. M. Kosarev 《Mineralium Deposita》2000,35(2-3):157-168
The Kochkar gold district in the East Uralian Zone of the southern Urals is located in late-Paleozoic granite gneisses of
the Plast massif. Gold mineralization is associated with tabular quartz lodes that are preferentially developed along the
margins of easterly trending mafic dykes. Fabric development indicates that dykes had a profound influence on the development
of shear zones in granitoids. ENE- and SE-trending dykes have been reactivated as dextral and sinistral oblique strike-slip
shear zones, respectively, forming a set of approximately conjugate shear zones related to the Permian, regional-scale E-W
directed shortening. Dyke-shear zone relationships in the Plast massif are the result of strain refraction due to the presence
of biotite-rich, incompetent dykes in more competent granite-gneisses. Deformation and the formation of associated gold-quartz
lodes occurred close to peak-metamorphic, upper-greenschist to lower-amphibolite facies conditions. Strain refraction has
resulted in partitioning of the bulk strain into a component of non-coaxial mainly ductile shear in mafic dykes, and a component
of layer-normal pure shear in surrounding granitoids where deformation was brittle-ductile. Brittle fracturing in granitoids
has resulted in the formation of fracture permeabilities adjacent to sheared dykes, that together with the layer-normal dilational
component, promoted the access of mineralizing fluids. Both ore-controlling dykes and gold-quartz lodes were subsequently
overprinted by lower greenschist-facies, mainly brittle fault zones and associated hydrothermal alteration that post-date
gold mineralization.
Received: 15 October 1998 / Accepted: 18 August 1999 相似文献
70.